Question

probability if 80% day 1, 90% day 2: can occur on either day or both days.

Answer 1

post the whole problem somthing is missing?
What does the question want you to do

Answer 2

Your thread before, you wrote "teest" I'm assuming applying "test". If this is a test, no one can help you and anyone who does could be suspended along with you.

Answer 3

That's no good!